Lattice Location of Ta in Ni3Ai by Ion Channeling and Nuclear Reaction Analysis

1986 ◽  
Vol 81 ◽  
Author(s):  
H. Lin ◽  
L. E. Sehberling ◽  
P. F. Lyman ◽  
D. P. Pope

AbstractWe have investigated the lattice location of Ta in Ni3Al using Rutherford backscattering with channeling, and nuclear reaction analysis. An 8 MeV 4He ion beam was directed along the < 100> crystallographic axis of the Ni75Al24Ta single crystal. A silicon surface barrier detector was used to analyze 4He ions backscattered from Ni and Ta atoms. Neutrons generated from Al by the 27Al(4He,n)30P reaction were detected by a large volume liquid scintillator placed outside of the scattering chamber. Essentially all of the Ta atoms were found to be substitutional, as determined by the Ta channeling minimum yield. A comparison of the width of the channeling angular scan for Al, Ni and Ta indicated that the Ta atoms are predominantly distributed on the Ni sites. This result is in conflict with expectations based on the ternary phase diagram.

2006 ◽  
Vol 16 (03n04) ◽  
pp. 231-237
Author(s):  
TAKUYA NEBIKI ◽  
TADASHI NARUSAWA ◽  
AKIKO KUMAGAI ◽  
HIDEYUKI DOI ◽  
TADASHI SAITO ◽  
...  

We have investigated the nitrogen lattice location in MOVPE grown Ga 1- x In x N y As 1- y with x = 0.07 and y = 0.025 by means of ion beam channeling technique. In this system, the lattice constant of the Ga 1- x In x N y As 1- y film is equal to GaAs lattice. Therefore, we can grow apparently no strain, high quality and very thick GaInNAs film on GaAs substrate. The quality of the films as well as the lattice location of In and N were characterized by channeling Rutherford backscattering spectrometry and nuclear reaction analysis using 3.95 MeV He 2+ beam. The fraction of substitutional nitrogen in the film was measured using the 14 N (α, p )17 O endothermic nuclear reaction. Our results indicate that more than 90% of In and N atoms are located the substitutional site, however, N atoms are slightly displaced by ~0.2 Å from the lattice site. We suggest that the GaInNAs film has a local strain or point defects around the N atoms.


1989 ◽  
Vol 157 ◽  
Author(s):  
J.A. Knapp ◽  
T.R. Guilinger ◽  
M.J. Kelly ◽  
D. Walsh ◽  
B.L. Doyle

ABSTRACTA key element of recent assertions of "cold fusion" has been the claim that electrochemical loading of deuterium into Pd electrodes can produce D:Pd levels exceeding 1:1. Using external beam nuclear reaction analysis of Pd foil electrodes in operating electrochemical cells, we have directly monitored deuterium content in-situ. No conditions were found which resulted in loadings higher than ∼0.9.


2005 ◽  
Vol 483-485 ◽  
pp. 287-290
Author(s):  
H. Colder ◽  
M. Morales ◽  
Richard Rizk ◽  
I. Vickridge

Co-sputtering of silicon and carbon in a hydrogenated plasma (20%Ar-80%H2) at temperatures, Ts, varying from 200°C to 600°C has been used to grow SiC thin films. We report on the influence of Ts on the crystallization, the ratio Si/C and the hydrogen content of the grown films. Film composition is determined by ion beam analysis via Rutherford backscattering spectrometry, nuclear reaction analysis via the 12C(d,p0)13C nuclear reaction and elastic recoil detection analysi(ERDA) for hydrogen content. Infrared absorption (IR) has been used to determine the crystalline fraction of the films and the concentration of the hydrogen bonded to Si or to C. Complementary to IR, bonding configuration has been also characterized by Raman spectroscopy. As Ts is increased, the crystalline fraction increases and the hydrogen content decreases, as observed by both ERDA and IR. It also appears that some films contain a few Si excess, probably located at the nanograin boundaries.


2002 ◽  
Vol 743 ◽  
Author(s):  
Eugen M. Trifan ◽  
David C. Ingram

ABSTRACTAn innovative approach for in-situ characterization has been used in this work to investigate the composition, growth mode, morphology and crystalline ordering of the early stages of growth of GaN films grown on sapphire by MOCVD for substrate temperatures in the range of 450°C to 1050°C. We have performed in-situ characterization by Rutherford Backscattering Spectroscopy (RBS), Ion Channeling, X-ray Photoelectron Spectroscopy (XPS), and Low Energy Electron Diffraction. Ex-situ the films have been characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and thickness profilometry. The films have been grown in an in-house designed and build MOCVD reactor that is attached by UHV lines to the analysis facilities. RBS analysis indicated that the films have the correct stoichiometry, have variable thickness and for low substrate temperature completely cover the substrate while for temperatures 850°C and higher islands are formed that may cover as few as 5 percent of the substrate. From Ion Channeling and LEED we have determined the crystallographic phase to be wurtzite. The crystalline quality increases with higher deposition temperature and with thickness. The films are epitaxialy grown with the <0001> crystallographic axis and planes of the GaN films aligned with the sapphire within 0.2 degrees.


MRS Bulletin ◽  
1987 ◽  
Vol 12 (6) ◽  
pp. 30-34 ◽  
Author(s):  
H-J. Gossmann ◽  
L.C. Feldman

AbstractThis article discusses uses of high energy ion beam scattering for materials analysis, including channeling, particle induced x-ray emission (PIXE), and nuclear reaction analysis (NRA). These additional capabilities used in conjunction with RBS equipment provide capabilities for crystalline defect studies and light element detection.


1992 ◽  
Vol 279 ◽  
Author(s):  
William R. Allen

ABSTRACTSingle crystals of silicon and diamond were implanted at 300K with 70 keV 3He. Ion channeling analyses were executed by application of Rutherford backscattering spectrometry and nuclear reaction analysis. Helium exhibits a non-random lattice site in the channeling angular distributions for silicon and diamond. A major fraction of the implanted 3He was qualitatively identified to be near to the tetrahedral interstice in both materials.


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